this is something ive been curious about for a long time and i have yet to see anybody actually talk about it so i thought youd be my best shot at an answer haha. is there a cultural reason as to why most of the characters exclusively refer to each other by their last names, regardless of how long theyve known them/how close they are? like for example nishiki & kiryu or saejima & majima? additionally, considering that the vast majority of the characters are referred to by last name, do you know why it is that a lot of the characters refer to daigo as. well daigo instead of dojima? like even during dead souls where he's still the chairman, when majima isnt referring to him as boss, he'll just call him daigo and wont even bother tacking on an honorific (Which lowkey i feel like is kind of insane considering hes literally the chairman, but i dont know if im supposed to read it that way LOL). any clarification would be much appreciated!
TL;DR: As with all character analysis, it’s most useful to take into account both intradiegetic and extradiagetic explanations. Cultural considerations, practical considerations, and individual character choices are inextricably entwined in-and-out-of-universe.
So… yes and no! Let’s first ignore the characters as they exist in-universe for a moment. In any exchange between characters, there’s one more listener to be accounted for: the audience. All dialogue is a dialogue between the author and the audience, and within this framework the names the characters use for one another exist at the intersection of culture and practical communication.
The name a character uses for another doesn’t only convey what their relationship is, but often also what the relationship between the other character and the audience (typically from the point of view of the protagonist) is meant to be. That’s why there’s reliable overlap between how a character is most often referred to and the name their dialogue is labeled with.
If Kiryu is “Kiryu” to everyone he knows, even those closest to him, he’s “Kiryu” to most of the audience, too. The audience (aside from hearing the subtle “ryu” sound as often as possible) is positioned to view Kiryu exclusively as someone to be respected—but not inherently to view him with affection, like the children, women, friends, and subordinates in Kiryu’s life who are referred to by given names and nicknames. Contrast this with Ichiban, labeled “Kasuga,” and how the people in his life and the audience refer to him.
I say “most of the audience” because some people do call Kiryu “Kazuma” by choice. Some people don’t know how to differentiate between given name and family name, or identify the wrong name as the family name. The author presumes a Japanese audience and the dialogue occurs in that context.
There’s also the subcultures around the works that went on to inspire the series, like ninkyo, v-cinema, and seinen manga. How, for example, have general attitudes towards gender lead to a highly gendered conception of chivalry? When male characters feel an instinctive protectiveness over and affection toward female characters and assume given-name familiarity with female characters they’ve just met, is this chivalry or a form of chauvinism? Are female characters not implicitly given less respect if they’re rarely or never referred to by family name, or not even given a family name? Where does this leave a trans female character like Ako, for whom using only her family name is akin to deadnaming her?
Alongside cultural considerations are the practical ones. What do you do if you have characters who are relatives and share a surname? But between Yuko and Akira Nishikiyama and Yasuko and Taiga Saejima, consider who defaults to given name and why. Consider how they’re introduced to the story and who’s introduced first. Consider their roles in the story and how what we’ve gone over so far may have contributed to their roles. These are all factors.
There’s also parent and child: Makoto and Saya Date, Jin and Ryuji Goda, Jiro and Ichiban Kasuga, and Masumi and Masato Arakawa. Arakawa is an interesting case; in the context of his whole family (Toshio, Yoko, Masumi, Masato), he’s actually referred to as “Masumi” instead. What about much larger families, like the Amon Clan? It’s simplest to refer to them by full name, but if I only say “Amon,” chances are you think of Jo Amon specifically. Why is that?
And last but not least, Sohei, Yayoi, and Daigo Dojima. Once cultural and practical considerations have been factored in, it’s worthwhile to look into individual characters. Luckily in Daigo’s case there actually is a canon, in-universe reason: he prefers to be called “Daigo.” We learn this in RGGO during an interaction with Mine, who previously insisted on calling him “Chairman Dojima.” Mine’s actually not the only one; plenty of people do call him “Dojima,” it’s more so that we spend the most time with characters who either would call him “Daigo” anyway or are aware of his preference.
As for Kiryu and Nishikiyama, I think Kiryu using a nickname for Nishikiyama (“Nishiki”) is perfectly in line with how closeness is typically conveyed, but in Nishikiyama’s case I can only speculate. Whether to use a given name or adopting a nickname is down to the individual; it signals closeness, in real life and in fiction, but changes nothing about the underlying relationship. Actors Yasukaze Motomiya and Yoshiyuki Yamaguchi and their characters (childhood friends) will sometimes use formal honorifics with each other in such a playful way that it comes across just as affectionate as a nickname, so you have to take it case-by-case.
It’s possible Sunflower was less family-oriented than Morning Glory—if we’re to view characters through the protagonist, the Morning Glory kids are all part of Kiryu’s family, but not all the Sunflower kids were. It’s possible Sunflower put more emphasis on the families the kids came from, perhaps due to Kazama’s guilt over killing their parents. It’s possible they were too old (or playing at being too old) to introduce themselves to each other by given name, or grew out of it. It’s also possible Yakuza’s writing simply didn’t take into account children tend to use given names with each other but Yakuza 3’s writing did.
Still, it’s worth examining: what does Kiryu using Nishikiyama’s nickname while Nishikiyama uses Kiryu’s family name suggest about the level of respect they have for each other and the distance between them?
Majima and Saejima are, on the other hand, most likely to have just been too old to be using given names with each other when they met. In Majima’s case, given he can be and often is overly-familiar, disrespectfully so, it’s more interesting to me that he isn’t when it comes to Saejima.
Finally, there’s also something to be said about how the characters have a tendency to hang on to past impressions of the people in their lives. The Arakawa Family, for example, and how their circumstances have changed beyond recognition but they’ll still call each other Boss, Captain, Young Master, Ichi, Mitsu. I think there are echoes of that sentiment among a lot of characters, past and present.
I have a lot of thoughts on names and titles and honorifics, but I’ll leave it there to (somewhat) stay within the scope of the original ask. I hope at least some of this has been helpful to you, and you’re welcome to ask for further clarification on anything at all.
